Source code for nifty8.operators.multifield2vector
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# Copyright(C) 2013-2021 Max-Planck-Society
#
# NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
import numpy as np
from ..domain_tuple import DomainTuple
from ..domains.unstructured_domain import UnstructuredDomain
from ..multi_domain import MultiDomain
from ..sugar import makeField
from .linear_operator import LinearOperator
[docs]
class Multifield2Vector(LinearOperator):
"""Flatten a MultiField and return a Field with unstructured domain and the
same number of degrees of freedom.
Parameters
----------
domain: MultiDomain
Domain of the operator
Notes
-----
This operator works only on MultiFields that have the same dtype for all entries.
"""
[docs]
def __init__(self, domain):
if not isinstance(domain, MultiDomain):
raise NotImplementedError("This operator only works on MultiDomains")
self._dof = domain.size
self._domain = domain
self._target = DomainTuple.make(UnstructuredDomain(self._dof))
self._capability = self.TIMES | self.ADJOINT_TIMES
[docs]
def apply(self, x, mode):
self._check_input(x, mode)
x = x.val
ii = 0
if mode == self.TIMES:
res = np.empty(self.target.shape, _unique_dtype([vv.dtype for vv in x.values()]))
for key in self.domain.keys():
arr = x[key].flatten()
res[ii:ii + arr.size] = arr
ii += arr.size
else:
res = {}
for key in self.domain.keys():
n = self.domain[key].size
shp = self.domain[key].shape
res[key] = x[ii:ii + n].reshape(shp)
ii += n
return makeField(self._tgt(mode), res)
def _unique_dtype(lst):
if all(ll == lst[0] for ll in lst):
return lst[0]
raise RuntimeError("Dtype is not unique")